A police investigation has found that a conveyor belt inside the Pike River Mine didn't cause a second explosion during the tragedy which claimed 29 lives in 2010.
Police say that following a thorough and detailed investigation into the design and operation of the conveyor belt, and after reviewing the known circumstances leading up to the second explosion, they found no evidence to suggest that the conveyor belt was operated or started at any time after the first explosion on 19 November 2010.
They also said that there was "no evidence of any causative link to the three subsequent explosions that followed between 24 and 28 November 2010."
The investigation focussed on a number of key areas, which included:
• The design and operation of the conveyor belt system
• The state of the mine at the time of the second explosion
• The proposal to start the conveyor and the risk assessment process.
Police said in a statement that the investigation found "no evidence that anyone gained access to a CCTV monitored hut near the mine portal where the conveyor belt was operated from."
It also found no evidence that anyone with the pre-requisite technical knowledge accessed the relevant computer systems to deactivate audible alarms which would have sounded prior to the belt being started.
The inquiry also established that the conveyor could not be started from the Pike River Coal Ltd control room.
On the second point police found no evidence after consulting with experts that there was an explosive atmosphere of gas adjacent to the conveyor system or allied electrical circuits, and no evidence that the atmosphere at the grizzly, where the belt ends, was anything other than fresh air.
On the third area the investigation examined risk assessment documentation regarding a proposal first raised by Pike River Coal Ltd staff to starting the conveyor belt.
There is no evidence that this proposal was supported or approved at any stage during the rescue phase, and no evidence that official authority to start the belt was issued by NZ Police or anyone else on 24 November 2010.
These findings confirm the initial police assessment of these claims which were made public in a media statement on 26 September 2018.
Police have met with members of the Pike River families today to communicate the outcome of the investigation.
The summary investigation report is available on the police website with further details.